1. Field of the Invention
The disclosed embodiments of the present invention relate to encryption/decryption, and more particularly, to a decryption engine and a decryption method.
2. Description of the Prior Art
In the encryption/decryption system such as High-Bandwidth Digital Content Protection (HDCP) 2.2, there are two steps in the decryption process of the receiving terminal. The first step is to complete an authentication flow with the transmitting terminal. The second step is to activate an Advanced Encryption Standard Counter (AES-CTR) engine to calculate a key, so as to use the key to perform the decryption process. However, if the transmitting terminal sends a wrong control signal during the decryption process, it will cause a synchronization failure. Once the synchronization failure occurs, the user can not see the normal image, and the user has to wait until the receiving terminal normally discovers and recognizes the synchronization failure, and the receiving terminal will send a re-authentication request to the transmitting terminal and recover from the error status via a long authentication process. It is very bad for the user experience, and thus an innovative method is required to solve the above-mentioned problem.